Combihatiow spool amd exmchtshiow holdee



Sept; 1927". L. a. TURNER 1,6423

' I I zmabfluc ham! I Original Filed Feb.l3, 1919 2 Sheets-Sheet 1 INVENTOR:

ATTORNEY L. B. Turner.

Sept. 20. 1927.

B. TURNER 'z LEcTRIc RELAY 2 Sheets-Sheet 2 Original Filed Feb. 13, 1919 ATTORNEY Patented Sept. 20,1927:

1 UNITED STATES PA FH LAunE'ivcn nrinnoiun rema n, or CAMBRIDGE, nus aun, ssmnon, HY mnsnnnssrsnmnnrs, r0 wnsrrnenousn ELEGTRIC.& MANUFACTURING COMPANY, A con- BOfiATiQN on PENNSYLVANIA.

nnnc'rmc RELAY.

Application-filed February 13, 1919, Serial No.

. This invention'relates to improved electric rela s andelectric relay circuits. 1

' =acuurn valves COIlSlStlIlg' of a glowing cathode-,I acoldfanode' and a grid or perfor-' a ated plate, all arranged in a vacuous, or

nearlyvacuous space, have hitherto been em ployed in. wireless telegraphy and other arts for magni: ing weak electric signals, for rectifying a ternatin'g currents, forgenerat- 10 ing electric oscillations, orforsome combination of-these functions. When used'as' an amplifier, the valve and its associated circuits are so' arr'angedthat a primary electromotive force of ismall' power -produces a 5 secondary, generally larger, electromotive force-"of fla'rger-power, .the wave form of which corresponds more or less to "the wave form'of the rimary electromotive force. The term-amp ifier as defined by the operation just referred to is used'in contradistinction totheterm relay, which latter term is intended to define an instrument wherein thev secondary. eflect. is produced by, but is not a' reproduction of, or proportional to, the :primary electromotive'force or current. The arrangement, forming the subject'- matter of the present invention. may be defined as a .valve-relay-for the reason that use ismade therein as a valve acting as-arelay in the sense above referred-to. The relay according to the present invention is similar tot-he more-or less mechanical relays ordinarily einployedin telegraphy with wires in the respectthat it lacks the proportionality between the effect and'the cause producing the same, and also in the respect that avery small primary power is sufficient to control a secondary power: greatly exceeding the controlledisecondary ower which is obtainable when the same va ve-is used as an amplifier in the Ordinary Way'. I

' It shas'r-previously been-proposed in con- I nection with electrical line'signaalling to re current by'm'eans of a transformerupon'an oscillating circuit associated with an I audion which. is adjusted to about the critical point at 1 which oscillation starts, thereby upsetting the -critical point and starting oscillation in 0 the saidci-rcuit; the resultant oscillatory cur rent, which persists only so long as the sig- .or other receiving device.

ceive' thesignals by superposiiig the received 276,856, and in Great Britain FebruarylB, 1918. Renewed Iu1y 5, 1923.

nal persists, being received, in a telephone It has also beenproposed in connection with the methodof rece ving signals 'ust referred to, to render audible a received current of inaudible frequenoy, by sub ecting such current to the action-of a ticker and causing the interrupted current to act through'a transformer upon an audion with which the receiving telephone is associated The invention consists in a valve relav cap-able of acting as a eneratorof oscilla t on, wl iich is adjuste to be in unstable equ librium at the critical point at which osc llat on sets in, and arranged to be set in oscillation by the action of a small electric current, thereupon continuing to oscillate irrespective of the continuance of the said operating current, the-accompanying increase in the mean anode current, or the oscillatory current, of the valve operating another relay, hereinafter referred to as a coarse relay or equivalent auxiliary indicating 'or relaying apparatus, and the oscillation being quenched by'a switching, or like operation, in order to restore the valve relay'to its original condition of equilibrium. I

The invention further consists in the relay circuits arranged and adapted to operate as hereinafter more particularly referred to. Inthe accompanying drawings illustrating the invention diagrammatically and by way of example Fig. 1 shows one invention,

' Fig. 2 is a diagram showing the well known curve of the anode current as a funcform according to the tion of the grid potential, and

Figs 3, 4, 5, 6, 7 and 8 are different modifications for carrying the invention into effect.

Referring to the drawings, V is a known form of vacuum valve arrangement comprising: a filament heated by means of a battery B, with which it forms a circuit hereinafter-referred to as the. filament 'circuit; a grid G connected to a battery 13,; by which in the stationary condition its potential is maintained at any desired value with respect to the potential of 'the iiegati've' end of the filament, this circuit being. hereinafter tuul induotuhoiii h :"ferrvd 1.0 as; the rid circuit; and. an anode A C(fl'iiTHfil'fii to a hattmy P1,. whi h i' l to nminiiuiniglo notm'itml pf the. a min libsixf'r t'iiv. potentia of (he atwo vm'i of {ins filamvni, this; circuitboing' herew- Mim I, ions the iu' odo uimuih. L

" died in bhewinmhi imriince inserted in the grid virouii. m x-1| of tin-s inductanci s bgiog ahunlmL by vondenseq: G 1nd respec-' tix'eiv (itiHJ' or both of \VhH'h condengsrrrg Wilt-1&1?" A TL 18 woii known that; ii. the vm'mus: parts "wink? Mme:

that as the grid pf Inggggitigk in its valve is not oscillatory, by causing a week signal to raise momentarily or periodically the potential of the grid, e. 11., by means of a suifahlo transforrnor'T T the osc'illwtion is stzillm], being accompanied by H large change of mean anode current.

The sudden change of tho mean anode curoflifi cixouit-s constituting the whole relay HI'X'HJIKQHIGHQi5 made self-rest ring; prefer i-ll ly by causing; the riisplarement of the spring cont-rolled tongue t of the oom so rei 1:13; to $(xop-oseillation. for instzinc'o, by short circuit-lug Um ix'aduct'ahccand mfztpacity I (f al'xtgmgod in the anode-circuit. Upon'fllo ce$satiim of l-t;ho oscillation, the relay tongoe'. ;,t ot'ui ns 1o its-former 'ositio'n, the process 16 coat-So Tolaiy CR; 85

they repeatodr :i

for another} coo-me rel xy; the magnets of which are' coi-mectad in Series or pa i'iilll Aft-er quenchi'ng, tho'sj'sigem pomains quiescent until 9.

fresh signal agai1\ ,mssos-the threshold. 11'

strong to induce in the s'econdary Tgof the lueioffheggrid; potential;

'. condcp'lof Shunt for,thewoscillatory blix I frontsbetweentho filament F .and'the eild ofg-the indliotancc 1 remote-- from the grid .(i,-and 'h'xiothox pomlenser.shunt between-"the --"fil-z mment*arid thood of the inductance L. remote "from; tho .:i i1odo, and such an a r- Husti'ated iii-Figure -3 in" gpysient tl lose; two; condensers It 'is' ho veyerto be understood mspectivef that 'althou-glr'the addition of some'cnpa'ci't may sometimes be .qonysidored, tobe: essentia theinherent. .solf-c I tlie cossatio i i of oscillation :is"qi1e n c11- I \imig ba'ttory' B 10 be ji tcd' j'iis t ij eiowihothreshold; and the ah. i ,rix iil ofgp sigr al in the primary T,,' ofthe.

tigjisf0rn'1eh momentarily-t0 raise the p0- Jim A fine adjustment of the grid potential may conveniently be obtained by the use of a potentiometer as illustrated for instance in Figure 3.

As the threshold depends upon the else trical dimensions of the circuits C l C I. and upon their mutual inductance, the same may be easily adjusted bYadjust ing the mutual inductance. The arrangement may be made to work with anythreshold provided it is towards the lower end of the curve a (Fig. 2). so that at the threshold there is unstable equilibrium. However,- in order to obtain the best results, it is desirable to arrange the threshold at a point where the slope of the curve a changes rapidly as the grid potential changes. The curve 6 in Figure 2 is drawn by makin the ordinates represent rate of change of sllope. Mathematically expressed, it 'v is the grid potential and i the anode current, curve a shows the relation between 2' and 1:, while 'L curve ?2 shows the relation between and It is desirable to have a threshold 2 at which is large. To get the best reisults. therefore, the threshold should be to be operative.

brought to a value at or near the summit of curve ('2.

'It is to be understood that the particular method of re-acting between the grid and the anode circuit shown in the various figures, is not the only method which may be used, as any other arrangement by which the system is rendered capable of generating oscillations may be emiiloyed instead.

Instead of the method 0 quenching hereinbefore referred to, use may be made of an independently operating switch for stopping: the oscillation.

The quenching device employed must remain in action for sullicient time to allow the energy-in ,the oscillatory circuits and the energy accumulated in the various other condensers arid inductances to fall sufiiciently to avoid automatic re-ignition of the oscillation when the quenching device ceases For this reason when T T is in iron coredtransformer adapted for signal currents of acoustic frequencies. it maybe desirable to keep the inductance of the secondary T. below the value which ycouldotherwise be chosen on consideralions oli s ensitiveness alone. For quenching: purposes it may also be desirable to intro- 'duceni dms m-increasing the rate of dissi' pat-ion oflhc energies stored in the several parts of the. circuits.

As the thresholddepends to a. certain extent omthe currentflowing through the tile.- ment, small variations of the po'tei'rtial dif ference of the filementljiuttery may conveniently be compensated by the insertion oi" resistence I in the filament circuit (see Fi 4) between the negative end of the filament and the point at w. ich the grid circuit joins the Sho t lit. The most eilective value of may be calculated by use. by me in a paper en- 5 .11 Devices. read before the ln ti l ost (lilies Electrical Enginsers, in February 1915. If the value of the resistance R is suitably chosen, the change of filament current accom nying a small change. of the 'otent-ial di chance of the filament battery 1.; produces a change of potential drop in the resistance R of such an amount that the grid potential still.

remains inst below the threshold.

The change in the grid potential may be effected in various ways according to the particular form of signal that is received.

According to one arrangement, the valve relay may be operated by telephonic currents, for instance through the intermediary of a transformer T T (see Fig. 1), the secondary of which is inserted in the grid circuit. thereby causing the operation of the course relay (TH through the anode circuit. the tongue 1% of the coarse relay being adapted to chatter as long as the signal continues. by rendering the whole of the device self-restoring hereinbeiore referred to, viz. by periodically short-circuiting the inductance arranged in the anode circuit during the reception of the signal. The secondary of the transformer and the winding of the coarse relay may be shunted by suitable condensers (l. and C} respectively.

The oscillation set up may be made of any high frequency. such as millions, or by any small frequent: such tens of periods per second. an intermediate frequency. by S'rlliilll choosing or ad usting the various capuciti... and indnctances. which latter may, or may not he provided with iron cores. The 1m: of :1 high frequency is found to be (onvenient in so far as the oscillation requires no appreciable time to be set up by the signal or to be stopped by the selfrcstoring device. and further if the oscillation frequency be very high compared with the frequencies of the operating currents for which the transformer connected with the grid circuit is made suitable. any alterations which may he ll'ected. or may take place. in the primary rircuit of the said transformer will ailc 't but little the adjust-u'icnts within the urn: ;emcnt described. it is also to be pi'ijntcd out that if it is. desired to obtain the highest.- degrcc of sensitiveness, the frequency of the oscillation should not be. lower than the frequency of the iucozuimc signal so that the duration of the trigger potential at the grid he snliicient for setting up the est en the operative are me high frequency currents ins gummy, sysicn'nr spark lransmiitcr I 591,11 prcriuccd in a telephone cpcmicd llirmigli th: lcccl contacts cf the coarse relay, or directly by the mean anode current, will retain par! of ill-P accust-ic character of signal, if the restoring device is arrangci'l so that it shall operate with a ire-- quency greatly exceeding lzhe acoustic frcquency of'i'ne transmitter.

in the case of incoming signals clue to high frequency curientz. such those wed in wflclcsr's tsilegiaphy ti'ifi high frequency cur-- rents may be applied directly in the grid williout being prcvii' usly lfli'ilfiG-(l lay the usual dctccior, this: being effected either through a traml'mmer whose secon lcry inserted in the grid circuit- 03. by magnetic inciiacticn m ie inductance alrcacy '0 inserted in the laltcr circui illustrates an ziz'rangemcnt axlaptcl'l for use in cn'nneciion with wireless signals. 1, is the aerial, '1}, is inductance incci i1. JB aerial and coupled witlitlic imluczazice T whilst is viriable coni cnsc'r inserted I: ll); aciial circuit, and 4 another vcrialilc wnclenser by which llic oscillatdry circuit i 4 is tuned to the aerial circuit and the incmning signal in the various arrangements licreinbefore more particularly rclcrrcd to with reference to Figures 1, 3, rr-nclcreci operative by the induction. in. the secc-mlal y T of the transformer 05 .m E M. E (inc in a change of mineral:- in the; primary T thereof. The ai'i'aiigcmcn', 311:1 however be adapted in be operated by sleady m: quasi-steady currents such as the ;signal cnrrcnis received over a submarine telegraph cable, for instance by causing such current or a part thereof flowing tlll'fillgll the prin'lary T of the transformer to be repeatedly changed, such as by breaking the circuit {cf T an independently ape-mil switch, F153 making the: time-constant of the circuit 0f 'l large. am ilie time during which ili current in T is built up alsc lasge, sufiicigt encrgy 5:0 he upcraiivc can be accumulated in the. transformer T '1; by the action if an extremely feeble signal current.

licfcrring: to iliec'imngcrncnt illustrated in Figure 6 5 i2 u telegraph cable er Gilletscarce nf stu ly or clmvly varying currens; 6 and 7 arc leads by which the current i5 mnvcvc l l'rnm the suirl cable to the primary T of the transformer, this bcing eficctccl through an interrupter which 1S Sl11l;3l3lfy mainf aineil in motion so as periodically to inteyru'nt the Si *lirougli the primary Ti: 21ml 10 a ii'ldil, contacts adapiecl i0 ce-o gcrctc wih the mevmg contact. 6

4 and 5, thcdcvicc is when 8 am! 9 are n t'mcurrcni', from i ,v ilm'mgh the primary T y are opcned i lllS mu'rcni -0 mm xvliei'elt y an ll. i i. F. imliicm 1n the smfznnrla 'y Fly :2?- ?zm ginfz that t i currcnt shall flow in the 1 s t iiircciicm, the iiirlucci'l M. F. may he 045ml momentarily to raise the potential of ilic P thereby setting the (system into us- A cnndansei' 11 may be armngcrl acinss the malaria Fl 21ml 9. Quenching may he cfiectcd in any 0f fhe manners; hereinlmfnra referred to. According to one 21rrangemcnh the quenching iscfi'eclerl by shortcircaiiting the inductance l bv means of the contacts 8 and 1. The mo zanlc conizlci 8 caused in vibrate m-twcen the iixcrl mniucts-z 9 and H3, ihm'eby alternately ex- (ming and igucncl'img tile uscillation as long as :z currcnt is reccivcd from the cable 5. The relay CR may be made sluggish that it shall not rcgistc the and brakes at U19. Ci. i cl sh i only {WEI/0125. to the slower nil lilac \"UXTQZlE z'eccivccl through the acts 9 'ng use 0% Well known means it 2.0 arrange that the rate of current in the primary T at vnmctbetween 8 and 9 shall be men; operate the. vnlvc relay. In this ca e, if reversal of current in T and '1,

allowing an ilic disturbance caused by the in'ccl: between the contacts 8 and 9, is pre- Real or kept suiliciently small, the device will respond :0 currents from the cable 5 in me 3.. rcc'ticu (mly. The reversal of current in the wii lings T and T 0f the transfmmcis may be checked 0y wholly prevent fl by tlic prcvision of damping devices in a well lmnwn manner, in: instance by means sit csismnce shunts l2 and 13 respectively.

It is somelimcs desirable or necessary to insert cm or incl-c amplifying valves between the source of signals and the oscillatory valve of thc relay. T'hc ncccssary w; for preventing reversal of currents grim cf the lDUHPOSQLl amplifying valve. Such. an azrazigcmcnt is illustrated in Figure '7 in W" cm VK, the amplifying valve.

u i. to a suiiablc Till) names:

den break of current in T ed from causing reversal of secondary T3.

The provision of an amplifying valve V has the further advantage that it more or less completely prevents a sudden rise and fall of current in the seconda T, from tending to throw currents into t e cable or other apparatus connected to the primary '1, of the transformer associated'with the am lifying valve V.

teady or relatively slowly varying E. M. Fs frequently occur in long cab es used in submarine telegraphy, which 'E. M. Fs give rise to currents tending to distort or obliterate the signals; this phenomenon is sometimes referred to as the wandering or inconstanc of the zero of the signals. When such a enomenon occurs, the E. M. F. induced m the secondary T. corresponds to the breaking of a current in the primary T consisting of two components. viz, the Sig nal current and the quasi-steady disturbing current, hereinafter referred to as the earth current.- In practice, it is found desirable to compensate for the earth-current. f i is the earth-current in the primer T,,. it produces in the secondary T, an i. M. F. proportional to i, viz, is i. wherek 1s a constant depending on the dimensions of the transformer T,,, T... and the rate at which the current falls when the contacts 8. 9 open. By arranging that the current i shall introduce another op )osing E. M. F.. is 12m the grid circuit I B without the s1gnal current producing a corresponding opposing E. M. F.. the effect of the earth-current can be nullified. ln producing the compensating E. M. F. in the grid circuit any of the known devices and methods for discriminating between earth-currents and signal currents may be utilized, and Figure 8 illustrates by way of example, one ar rangement whereby the earth-currents may be made to produce the desired compensatin E. M. F. i

ieferring to Figure 8. r [S a res stance of compact form inserted in the rid circuit and consistin of a fine wire 0 copper or other materia having a large temperature coeflicient of resistance and adapted to be strongly cooled by a Cooling body 14 ar ranged in its proximity. The resistance 1' is arranged in series with another resistance r and a battery B whereby the resistance 1' is maintained at an elevated temperature and a potential difference is produced across it whiqh rises and falls the temperatur of r rises and falls. The cooling body 14. which may consist oi a plate of aluminium or copper or other good heat conduct ng material, is provided with a large C0Olli|f surface for the rapid ilisipation of heat and is attached to the moving vsystem 15 of a sensitive galvanometer or quivalent apcan be prevent- E. M. F. in the paratus. through the coil of which the earth-currents, or a part thereof, are caused to pass. In Fi are 8 the usual condenser 16 shunted by t e resistance 17 and inductance coil 18 of large time constant are shown, the current in 16 being made to flow through the galvanometer coil 15. Part of this current may if desired be shunted away from coil 15 by the resistance 19 which may possess inductance. The re sistance '1' and the cooling body 14 are shaped and relatively arranged in such a manner that the temperature of the former is greatly affected by the motion of the latter. If the coil of the galvanometer car ries any considerable portion of the signal. currents the galvanometer is made extremely sluggish in action by known electrical or mechanical means or both. so that While the quasi-steady ;;-arth-currents are capable of producing an appreciable deflection of the galvanometer, the latter cannot follow the rapidly reversed signal currents. If an earth current 2' produces a rise tential k i. and if the galvanometer is arranged so that the same current causes the cooling body 14 to move away from the resistance r. the parts must be so dimensioned as to make the change of potential difference across r as nearly as possible equal in magnitude to k i, and the battery B. must be connected in the sense shown on the drawing. In the case of a code bein employed such as those associated with the names of Gott and Picard, in which the mean signal current is zero, signal currents in the ga vanoineter coil do not appreciably deflect the galvanometer. With other codes, however, such as the ordinary siphon recorder code, in which the means signal current would be zero only if the dots and dashes were equal in number, it is necessar in adjusting the grid potential to make a lowance for the deflection of the cooling body 14 produced by the average signal current durin the reception of the signals, and it is desire le to prevent its much as possible the signal currents from entering the galvanometer coil. for instance in the weil known manner. by making its inductance as large as possible and by roviding a shunt of small impedance wit respect to the signal currents. or by any other suitable means. I

The various methods of high frequency and acoustic frequency tuning may be used in connection with the various circuits emplayed in the arrangement hereinbefore described. Fmther. as the arrangement described is essentially a potential operated and not a power operated relay. the tuning may. under certain conditions, be carried to a finer pitch than is possible with most receivers where the power absorbed by the die actor is far from being negligible.

of grid p0 iao.

&

I (Rpm- 5mg from {he spirifi 0f the inveniinn.

K aim; wish. ii m be umim'stoud ma; (1m invcntion in nu way dependeut on the them" hereinbefore ad'vancad f0: explaining he vuria'us phemm lena invuEved in the mm nf aciing as gen .z''hy it mrv bs afijusiv? (:0 M in unstabie equiiiku'iuu: a; the cntimi puini which usa 'fiaiun sets in, and arrzuxgm? m be 3% in osc iiatwn by astzon 9f 1. 51ml! elects-h;- wrxenfi, @hufeupun continuing to osciilsm: irr ne-c' w uf th continuance of tha sair i 1:. A vs e1w: &}.3a} v 1 m a gen eratm of mci l mhon, wniuh is acijmted to be in nnstabi iiiih'inmz M the v its puim 2L wiflufn Mum-1m and arranged is he wt. in wrci imtiwn the amim: 0i mull 91v iixln vun'ent, UIPFBUPUH (:uni nmng in 5-5 Milan:- 5:" peciixu'af the wmlnuw'uiz 01' the: said operating: (ulna? in combiami on 1 an QPPHII'LJCUSK 5&1: Eve than the waive relay and arraugwi (2 mapmuxaci by the, m:(:mn m11ying 311-; in the. cusrrut 0f the valve, and will: imam f0; quenching the f'iilation switvhl pg -:;-pe;'a;mu. wheraby the Valve relav is rvstowed to its: 01 {mal currdition nf equilibrium, said "{m'enchiug means (:unfi ating of a circuia capable a)? shmb cinruiting L 10 U51-Ci1111uk drama umber Hm comm? 0.? 1 has sensitive appummsz, an 455 forth.

3 A valve relay Capable 0f acting as (a gen-- emlm of main-M1011, means whez-uy it may b4: yijust d L0 be in unwiable equilibrium at the Critical palm. M which osciiizviilm sets in, and armmyrd H3 be 5m in osqiiiation hy the mitiim of a snail ejfiuctzic (*urrenh thereuwn .x.mtinuing m oscillate irrespective of Hm cemimmxii'i: of (be said (rpmsling rrm'renh in mmBinatim; with an :ig paratum K'Jhluh ass sensitive. :l'mn the alve why and, z: lfllifi'ifivd to be operated by the accazmpanying increase: in the mean. made curry with mams fe mamas:

fllifildfiii? 1; tlw nsci relay is 1' stored to its original (mm aqu'ziibrium, and with maxim far seizing .35: L mrriiliaiiiun by tin: m-tinn of a slur-(i! r1? 11mm in m'mni, 31*. set Earth.

it A waive relay 031521312 :2? a: rim; as a wzr mtm 0? a Ruffian" which is mm! Lu In: in unstable equiiibrium at the (TESQQE at which asi' iiutiun sets in. and m-x'aug bv set m OSCillfitiuY'i by the aviion 01 a small flea-iris current, thureupen continuing t0 still-w; awe 'estiva of the winiinnarms m? Hm said operating (:mrei'm in comnimuiura with an appamius which is Bess sensitive than the valve r9221 and is :agrmnged to be operated by i accompany inc: a in the 331-35111 .mfifldit current, of the M 10,

' the 4 "Eat am and *zmrsas'iing a, amt whim: is; a

iii. the chunk in which m6 0;; .119." 7 i4 .wbv ihz, wai e relay EKESMHfPt' it its urignmi wndiam. of aquihhrium 5, kppzuams for rec'ezving and mm ingg wan: signals, and mm x'ising in CUJL Hnutiom, 1110mm I'm: pvmiucmg $J-1i11i031b Mn} ism-Ending, an ampiiiying waive. a-z .mhki t9 be trigged", ans auizunatimiiy 01mm? img uiwirxa'i Imam mike up; fi'w uifmilm firu'zii' (sf the vain? =1 qua-Wham the ofi si iiaiions m; EQd.

ti Appam iua fox Receiving {1214K rm Wave ugnnis and wmprsing in can a fevd'wuk sysmn'h and means 50y 3)" 1y aitwin mlaiion betwem the a "zmuii of fwd-5am and the degree of Ian i a? 3: syfiem,

%. Apparatus for z wi .ais and camnprisn a feedback lzition whmeby Gav a 5 waw. J

m pmrmm, be 1mm a ee6bmx a} 5mm Minster mar the pomt of oscaiiatmn; and msam; for her.-

odicniiy varying 51w amount of fzmfb wk with respeit t0 the damping of mid s" 10. The metlwd 01' receiving and ampiiiy ing signals transmitted from a. d "am-e which comprises impr ing varying rial representing the incoming signal amplified upon a fecdbacb system. and lh odical iy altering the ielation b twem Um: zunount in feedback and the degree 0L damping-g nf the system.

I 1.. The nmthod of receiving and ampll! an :signals transmittal fmm dlSt-anw; wan-ch comprises ixupressl m var-yang potential representing the 2 212011 signals; L by amplified 1. 1011 a feedback micul f, l pen ullically urging the mnuunt of felylliack.

LE; The mctllml of receiving; and mnpl i in" signal; u'ansmlttml from a distance I: c Jlnyris-ms nlzyz'vwlng varying iJOLClr tiul rcpresentmg rim mourning signals to bg amplified upon :1 feedback systmu adjusted near the point at oscillation; and simultaneously jv 104mm; varying the amount of femllnn-k with IQbPeCL t0 the damping.

l3. Appumtw for receiving and amplifying sag-1m. a tn Innis-d. l'z'um a distance and wungnning 1n combinatiun, a fucdbacl; tvm, 1' wing means for iznpwssing upon said s wl-znn x'm'y ng pntential representing ant lDK'Ullllli liills to M: amplified, and means in) 11c: ntnlimlly altering the relation be? Em nnaunnt vi feedback and Lllc (lmglu 11f (lumping 0f tin; =4 ism.

H. xt ggamtm; lui' rum-lying anal amplify- I transmitted 1mm Ll, distance and r'mn iu'iajng in rmnbinatloln a feel'lbzmk cir- (full? upon whnh the yotential 0! mid signals, l:-; :nlnpuui to be impre and, remivl means fur nnpw ring upon gain circuit. \zu' mg 1H llti tll mpnwntzng the jnwlning signals to by umplfiul, and means {or pm'mnllually 'l'itl'j'llig' the unn' unt nl' lcmlbasli in said fill bank with aymam.

' 52;. Apparatus for rum-mm; I amplify ."mls transmit I from a zstm'me and An in tromluauun i iwlhack Sys- 5 n-mmmg means, 3%; 1 mslng upon will syflmn varying n; x ill representing Ilm incoming signal:v ennyliliell means l ul pe-zwlirmlly il li. LClilKlOI! betwmm line amount of w and the degiu: 0f (lumping ul' ti stun and signalrmllvuilng means cmztm ll lg; the current in the output tillulill' n5 idurl feedback sys- 1cm.

1?. Apparatus for :wlwlng and amplifying :siynnl u'unsmitlw 51m. n all stance and unnprmng in wmbm .L inedlmck cir- (my ulmu wlm'll tlug: poten ial 03? said signals in UlilJIUJll m be ilnprm rnutivlng means I'm: ixnpr-;.--,slng upon mini viruuit varying p0- tmtiui wpuwnung UH: nnzmnxng signals to in: znnplihml, menus, lkn -mmni Varyin the HUNT-l 01' l'eellb-A will circuit, an .ig;n;alZm1ualEng mama. Wntrulled by the vliilvlll in the output unruit of Said feedback urcuit. lb. Apparatus 1 ru ning and amplifymn liflllllb' Uzulslnltlmi um a distance and uulnpx'i-;lr1g in cumhinutiam, a feedback syslmn :|\lj:,1,--tu i 1105: tln; pumt of oscillation, receiving mums [or imyz'gsslng upon Said .s ylmn varying potential z's-premzuting the inv-nnin; lgllllln' m be mm, means for puriurlmully \nryjn (1n: .nnuunt 0f feedhurl; it}; rmpuct to {in dum ing (if the sysin), and ngnul-jnlliuzuz nmms controlled in; lln: student in [ln out nut circuit of said ik-wlilz l; mystmn.

LA Ull Ii 0 I51 1'; El) DOM in T U RNER.

respect in the *laznpirg of the 

